Ophthalmic image pickup apparatus

ABSTRACT

To provide an ophthalmic image pickup apparatus capable of setting a fixation target in a position suitable for image pickup in accordance with a selection of an image pickup purpose (group medical examination such as an adult disease examination or a glaucomatous examination). In addition, it can be determined whether operation of the fixation target is inhibited or allowed in accordance with the selected image pickup purpose.

This is a continuation of prior application Ser. No. 10/463,276 filedJun. 17, 2003, to which priority under 35 U.S.C. §120 is claimed.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to an ophthalmic image pickup apparatusused in an ophthalmic doctor's office, for a group medical examination,or the like.

2. Related Background Art

Up to now, a fixation target for leading the line of sight of an eye tobe examined is provided in an eye fundus image pickup apparatus. Forexample, there are the following settings related to the fixationtarget.

In eye fundus image pickup in an ophthalmic section of a hospital or thelike, an image of different ophthalmic diseased regions is picked up foreach patient in many cases. Accordingly, the fixation target is moved tolead the line of sight of the eye to be examined so that an image of aregion which is most effective for diagnosis can be picked up. Incontrast, in the case of the eye fundus image pickup in a group medicalexamination, it is unnecessary to move the fixation target because animage pickup region is determined according to an examination purpose.

Thus, the movement of the fixation target is made effective in the caseof eye fundus image pickup in the ophthalmic section and the movement ofthe fixation target is made ineffective in the case of the eye fundusimage pickup in the group medical examination.

Also, in the case of the eye fundus image pickup in the group medicalexamination, because the image pickup region is changed for eachexamination purpose, the position of the fixation target is changed. Forexample, in the case of eye fundus image pickup in an adult diseasesexamination, the fixation target is provided in a position in which thecenter between an optic disk and a macula lutea in the eye to beexamined becomes the center of image.

In the case of eye fundus image pickup in a glaucomatous examination,the fixation target is provided in a position in which the optic disk ofthe eye to be examined becomes the center of image. In the case of eyefundus image pickup in a macular degeneration examination, the fixationtarget is provided in a position in which the macula lutea becomes thecenter of image. Thus, the fixation target is provided in the positioncorresponding to the purpose such as the eye fundus image pickup in theadult disease examination, the eye fundus image pickup in theglaucomatous examination, or the eye fundus image pickup in the maculardegeneration examination.

However, in the above-mentioned conventional examples, there are thefollowing problems. When the eye fundus image pickup in the ophthalmicsection and the eye fundus image pickup in the group medical examinationare conducted, in particular, when the purpose such as the adult diseaseexamination, the glaucomatous examination, or the macular degenerationexamination in the group medical examination is changed to conduct theeye fundus image pickup, it is necessary to reset plural settingsrelated to the fixation target. Therefore, it takes much time andefforts for a person picking up an image and it is extremely burdensome.Further, when there is omission in settings related to the fixationtarget, there is a fear of causing an unexpectable operating error.

SUMMARY OF THE INVENTION

An object of the present invention is to solve the above-mentionedproblems and to provide an ophthalmic image pickup apparatus in whichimage pickup is easy, there is no omission of its setting, and a settingrelated to a fixation target can be simply performed in the case where apurpose such as eye fundus image pickup in an ophthalmic section, anadult disease examination, a glaucomatous examination, or a maculardegeneration examination is changed to perform eye fundus image pickup.

In order to achieve the above object, according to the presentinvention, there is provided an ophthalmic image pickup apparatusincluding: a fixation target for leading a line of sight of an eye to beexamined; a purpose setting unit; a fixation target moving methodstoring unit for storing a moving operation method of the fixationtarget corresponding to a purpose set by the purpose setting unit; and afixation target movement control unit for moving the fixation target inaccordance with the moving method of the fixation target whichcorresponds to the purpose set by the purpose setting unit and is storedin the fixation target moving method storing unit.

Also, according to the present invention, there is provided anophthalmic image pickup apparatus including: a fixation target forleading a line of sight of an eye to be examined; a purpose settingunit; a fixation target presenting position storing unit for storing apresenting position of the fixation target corresponding to a purposeset by the purpose setting unit; and a fixation target presentingposition changing unit for presenting the fixation target in thepresenting position of the fixation target which corresponds to thepurpose set by the purpose setting unit and is stored in the fixationtarget presenting position storing unit.

Further objects and structures related to the present invention will beapparent in explanation of the embodiment below.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a structural view of an ophthalmic image pickup apparatus foran eye fundus;

FIG. 2 is a front view of a liquid crystal display unit;

FIG. 3 is an explanatory view of eye fundus image pickup in an adultdisease examination;

FIG. 4 is an explanatory view of eye fundus image pickup in aglaucomatous examination;

FIG. 5 is an explanatory view of eye fundus image pickup in a maculardegeneration examination;

FIG. 6 is a flow chart for eye fundus image pickup; and

FIG. 7 is an explanatory view of a right-and-left-eye selectiondetecting switch.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

The present invention will be described in detail with reference to anembodiment shown in the drawings.

FIG. 1 is a structural view of an ophthalmic image pickup apparatus ofthis embodiment. On an optical path O1 in the front of an eye to beexamined E, an objective lens 1, an anterior eye part observing lens 2which is insertable onto the optical path O1, a holed mirror 3 having animage pickup diaphragm 3 a in its hole portion, a focus lens 4 which ismoved along the optical path O1 to adjust a focus, an image pickup lens5, a selection mirror 6 for reflecting a visible light and transmittingan infrared light, and an image pickup unit 7 are disposed in order. Inaddition, anterior eye part illuminating light sources 8 for emittingthe infrared light are disposed in the vicinity of the objective lens 1.

An eye fundus illumination system 9 is disposed on an optical path O2 inthe light reflecting direction of the holed mirror 3. According to theeye fundus illumination system 9, an eye fundus Er of the eye to beexamined E is irradiated with the infrared light at the time of eyefundus observation and the eye fundus Er is irradiated with the visiblelight at the time of eye fundus image pickup. In addition, a liquidcrystal display unit 10 for displaying a fixation target in a positionsubstantially conjugate with the eye fundus Er and an illumination lightsource 11 for illuminating the liquid crystal display unit 10 from itsrear side with the visible light are disposed on an optical path O3 inthe light reflecting direction of the selection mirror 6.

FIG. 2 is a schematic view of the liquid crystal display unit 10. In theliquid crystal display unit 10, a plurality of cells which are each madeof liquid crystal and capable of setting a transmission state or anontransmission state are arranged in matrix. When a cell in which thetransmission state is set is assumed to be an opening portion “A” and acell in which the nontransmission state is set is assumed to be a lightshielding portion “B,” of lights emitted from the illumination lightsource 11, a light transmitting through the opening portion “A” isreflected by the selection mirror 6. The reflected light passes throughthe image pickup lens 5, the focus lens 4, the hole portion of the holedmirror 3, and the objective lens 1 and reaches the eye fundus Er througha pupil Ep of the eye to be examined E. In other words, an image of theopening portion “A” is presented on a dark background as the fixationtarget for a person to be examined in which the pupil Ep is located onthe optical path O1 of the objective lens 1.

An output of the image pickup unit 7 is connected with a televisionmonitor 13 through an image control unit 12. Further, an output of theimage control unit 12 is connected with a function control unit 14 forcontrolling the entire apparatus. The function control unit 14 isconnected with the liquid crystal display unit 10, a fixation targetmovement operating switch 15 for controlling a presenting position ofthe fixation target, that is, a position of the opening portion “A” ofthe liquid crystal display unit 10, an anterior eye part and eye fundusselecting switch 16 for controlling whether or not the anterior eye partobserving lens 2 is inserted onto the optical path O1, aright-and-left-eye selection detecting switch 17, an image pickup switch18, a memory 19, a purpose selecting unit 20 for selecting a purposesuch as eye fundus image pickup in an ophthalmic section, an adultdisease examination, a glaucomatous examination, or a maculardegeneration examination, and a purpose-by-purpose fixation targetsetting storing unit 21 for storing settings with respect to movementoperation of the fixation target and a presenting position thereofaccording to the purpose.

The following Table 1 shows a summary of the purpose-by-purpose fixationtarget setting storing unit 21. In the case of the eye fundus imagepickup in the ophthalmic section, the fixation target is moved to lead aline of sight of the eye to be examined E so that image pickup can beperformed for a region which is most effective for diagnosis. Therefore,a movement operation of the fixation target using the fixation targetmovement operating switch 15 is made effective. In addition, in the caseof the eye fundus image pickup in a group medical examination such as anadult disease examination, a glaucomatous examination, or a maculardegeneration examination, it is unnecessary to move the fixation targetbecause an image pickup region is determined according to a diagnosticpurpose. Therefore, a setting is stored so that the movement operationof the fixation target is made ineffective. TABLE 1 Fixation FixationTarget Target Fixation Presenting Presenting Target Moving PositionPosition Purpose Operation (Right Eye) (Left Eye) Ophthalmic Effective(RX1, RY1) (LX1, LY1) Section Adult Disease Ineffective (RX2, RY2) (LX2,LY2) Examination Glaucomatous Ineffective (RX3, RY3) (LX3, LY3)Examination Macular Ineffective (RX4, RY4) (LX4, LY4) DegenerationExamination

A relationship between a fixation target presenting position in theliquid crystal display unit 10 and a position of a macula lutea “m” onan eye fundus image imaged onto the image pickup surface of the imagepickup unit 7 is obtained from optical design values of the ophthalmicimage pickup apparatus and optical data of a standard eye. From thisrelationship, the fixation target presenting position is set accordingto the purpose.

FIG. 3 is a schematic view of the eye fundus image pickup in the adultdisease examination. In the eye fundus image pickup in the adult diseaseexamination, in order to locate a macula lutea “m” in a position shiftedfrom the center “c” of an image by only ½ of a distance between an opticdisk “d” and the macula lutea “m,” a fixation target presenting positionis calculated from a relationship between the above-mentioned fixationtarget presenting position and the position of the macula lutea “m” onthe eye fundus image. When a person to be examined gazes the fixationindex presented in the calculated position, the center of image “c”becomes the center between the optic disk “d” and the macula lutea “m”in the eye to be examined E.

FIG. 4 is a schematic view of the eye fundus image pickup in theglaucomatous examination. According to the eye fundus image pickup inthe glaucomatous examination, in order to locate the macula lutea “m” ina position shifted from the center of image “c” by only a distancebetween the optic disk “d” and the macula lutea “m,” a fixation targetpresenting position is calculated from a relationship between theabove-mentioned fixation target presenting position and the position ofthe macula lutea “m” on the eye fundus image. When the person to beexamined gazes the fixation index presented in the calculated position,the optic disk “d” of the eye to be examined E becomes the center ofimage “c.”

FIG. 5 is a schematic view of the eye fundus image pickup in the maculardegeneration examination. In the eye fundus image pickup in the maculardegeneration examination, in order to locate the macula lutea “m” in thecenter of image “c,” a fixation target presenting position is calculatedfrom a relationship between the above-mentioned fixation targetpresenting position and the position of the macula lutea “m” on the eyefundus image. When the person to be examined gazes the fixation indexpresented in the calculated position, the macula lutea “m” of the eye tobe examined E becomes the center of image “c.” Note that the fixationtarget presenting positions corresponding to these purposes are set andstored in the purpose-by-purpose fixation target setting storing unit 21as shown in Table 1.

Thus, the fixation target presenting position is set for each of theright eye and the left eye. Note that the fixation target presentingposition for the eye fundus image pickup in the ophthalmic section maybe set an arbitrary position because it is assumed to move the fixationtarget.

In the ophthalmic image pickup apparatus having such a structure, aprocedure in the case where an eye fundus image is picked up by a personpicking up an image will be described with reference to a flow chartshown in FIG. 6. First, a power source switch (not shown) is operated tostart the operation of an ophthalmic image pickup apparatus main body.In step S1, an intended purpose such as the eye fundus image pickup inthe ophthalmic section, the eye fundus image pickup in the adult diseaseexamination, the eye fundus image pickup in the glaucomatousexamination, or the eye fundus image pickup in the macular degenerationexamination is selected by the person picking up the image. In addition,the selected purpose is stored in the memory 19.

After the completion of the purpose selection in step S1, an anterioreye part is observed in step S2. In a state in which the anterior eyepart is observed, the anterior eye part observing lens 2 is insertedonto the optical path O1 and the selection mirror 6 is located on theoptical path O1. With this state, an anterior eye part image resultingfrom the illumination with an infrared light emitted from the anterioreye part illuminating light sources 8 is passed through the objectivelens 1, the anterior eye part observing lens 2, the hole portion of theholed mirror 3, the focus lens 4, and the image pickup lens 5. Theanterior eye part image is imaged onto the image pickup surface of theimage pickup unit 7, converted into a video signal, and displayed on thetelevision monitor 13 through the image control unit 12.

While viewing the picture displayed on the television monitor 13, theperson picking up the image operates an operation stick (not shown).When alignment with an eye to be picked up, for example, the right eyeis completed, the function control unit 14 determines that the alignmentwith the right eye is completed in accordance with the output of theright-and-left-eye selection detecting switch 17.

FIG. 7 is an explanatory view of the right-and-left-eye selectiondetecting switch 17. A stage 32 is located above a base 31 and theright-and-left-eye selection detecting switch 17 is fixed onto the lowersurface of the stage 32. The stage 32 is constructed such that it ismoved in the lateral direction indicated by an arrow in the figure.

When the stage 32 is moved in the lateral direction, an on/off of theright-and-left-eye selection detecting switch 17 is switched.

After the alignments with the right eye is completed and anterior eyepart and eye fundus selecting switch 16 is operated, processing istransferred to an eye fundus observation in step S3. In this eye fundusobservation state, the anterior eye part illuminating light sources 8are turned off, the anterior eye part observing lens 2 is left for theoutside of the optical path O1, the selection mirror 6 is located on theoptical path O1, and an infrared light is emitted from the eye fundusillumination system 9.

The infrared light emitted from the eye fundus illumination system 9 isreflected on a mirror portion of the circumference of the holed mirror 3to illuminate a region from the pupil Ep to the eye fundus Er throughthe objective lens 1. An eye fundus image resulting from theillumination is passed through the pupil Ep, the objective lens 1, thehole portion of the holed mirror 3, the focus lens 4, the image pickuplens 5 and the selection mirror 6. The eye fundus image is imaged ontothe image pickup surface of the image pickup unit 7 and converted into avideo signal, and then displayed on the television monitor 13 throughthe image control unit 12. In addition, in this eye fundus observationstate, the fixation target is presented in the fixation targetpresenting position stored in the purpose-by-purpose fixation targetsetting storing unit 21 in accordance with the aligned eye of the rightand left eyes and the purpose selected in step S1.

Subsequently, when the eye fundus image pickup in the ophthalmic sectionis selected as the purpose in step S4, the processing goes to step S5. Afixation target presenting position for right eye (RX1, RY1) which isused for the eye fundus image pickup in the ophthalmic section andstored in the purpose-by-purpose fixation target setting storing unit 21is set as the opening portion “A” of the liquid crystal display unit 10.Other regions are set as the light shielding portions “B.” Then, theillumination light source 11 is turned on to present the fixationtarget, thereby leading the eye to be examined E.

Also, when the eye fundus image pickup in the adult disease examinationis selected as the purpose, the processing goes to step S6. A fixationtarget presenting position for right eye (RX2, RY2) which is used forthe eye fundus image pickup in the adult disease examination and storedin the purpose-by-purpose fixation target setting storing unit 21 is setas the opening portion “A” of the liquid crystal display unit 10. Otherregions are set as the light shielding portions “B.” Then, theillumination light source 11 is turned on to present the fixationtarget, thereby leading the eye to be examined E.

Note that descriptions with respect to the eye fundus image pickup inthe glaucomatous examination and the eye fundus image pickup in themacular degeneration examination are omitted in the flow chart shown inFIG. 6. However, as in the case of adult disease examination, a fixationtarget presenting position (right eye) for a corresponding purpose whichis stored in the purpose-by-purpose fixation target setting storing unit21 is set as the opening portion “A” of the liquid crystal display unit10. Other regions are set as the light shielding portions “B.” Then, theillumination light source 11 is turned on to present the fixationtarget. In this eye fundus observation state, a precision alignmentbetween a main body optical system and the eye fundus Er of the eye tobe examined E with respect to longitudinal and lateral positions and aworking distance is conducted by the operation stick (not shown). Inaddition, the focus lens 4 is moved along the optical path O1 to makefocusing.

In the case where the eye fundus image pickup in the ophthalmic sectionis selected as the purpose, when the fixation target movement operatingswitch 15 is operated in step S7, the opening portion of the liquidcrystal display unit 10 is moved in step S8 to move the fixation target,thereby leading the line of sight of the eye to be examined E. On theother hand, when the eye fundus image pickup in the adult diseaseexamination is selected as the purpose, the fixation target presentingposition is fixed. Therefore, the operation of the fixation targetmovement operating switch 15 is made ineffective.

With respect to the eye fundus image pickup in the glaucomatousexamination and the eye fundus image pickup in the macular degenerationexamination, the operation of the fixation target movement operatingswitch 15 is made ineffective as in the case of adult diseaseexamination. Then, the line of sight of the eye to be examined E is ledto the fixed fixation target presenting position.

When the precision alignment, focusing, and the leading of the eye to beexamined E are completed, the eye fundus image pickup is performed byoperating the image pickup switch 18 in step S9. When the person pickingup the image operates the image pickup switch 18, the selection mirror 6is left for the outside of the optical path O1 and the image pickup unit7 starts optical storage for still image pickup. In addition, the eyefundus illumination system 9 emits a visible light, so that the eyefundus Er of the eye to be examined E is illuminated with the visiblelight as in the above-mentioned case of the infrared light. An eyefundus image thus illuminated is passed along the same path as in theabove-mentioned case of the infrared light and imaged onto the imagepickup unit 7. The still image is converted into digital data by theimage control unit 12, stored in an image memory of the image controlunit 12, and displayed on the television monitor 13.

Note that, in this embodiment, only one cell of the liquid crystaldisplay unit 10 is set as the opening portion “A” to present thefixation target. A plurality of cells may be set as the opening portion“A” to present the fixation target. Further, when a plurality of cellsmay be set as the opening portion “A,” a fixation target with anarbitrary shape can be presented.

Also, in this embodiment, the fixation target is presented and movedusing the liquid crystal display unit 10 and the illumination lightsource 11. The fixation target can be presented and moved by a fixationtarget light source composed of an LED, a motor for controlling aposition of the fixation target light source, and the like.

Further, immediately after the power source is turned on, the purposesuch as the eye fundus image pickup in the ophthalmic section, the eyefundus image pickup in the adult disease examination, the eye fundusimage pickup in the glaucomatous examination, or the eye fundus imagepickup in the macular degeneration examination is selected by thepurpose selecting unit 20. However, the purpose may be selected exceptfor a time point immediately after the power source is turned on.

Note that in the case where a nonvolatile memory is used as the memory19 and the selected purpose is stored in the nonvolatile memory, whenthe power source which is operated to start the operation of the mainbody, settings with respect to the movement operation of the fixationtarget for the previous selected purpose and the presenting positionthereof can be conducted without selecting the purpose.

Most of the above-mentioned processings can be realized by programs.Therefore, even when a recording medium in which program codes of asoftware for realizing functions of the above-mentioned embodiment arerecorded is supplied to a system or an apparatus and a computer (CPU orMPU) in the system or the apparatus reads the program codes stored inthe recording medium and executes them, the present invention can berealized as a matter of course.

In this case, the functions of the above-mentioned embodiment arerealized by the program codes themselves read from the recording medium.The recording medium in which the program codes are recorded constructsthe present invention. A floppy disk, a hard disk, an optical disk, amagneto-optical disk, a CD-ROM, a magnetic tape, a nonvolatile memorycard, a ROM, or the like can be used as the recording medium forproviding the program codes.

In this embodiment, the eye fundus camera is described and a slit lampcan be similarly constructed.

As described above, in the ophthalmic image pickup apparatus accordingto the present invention, there are provided the purpose selecting unitfor selecting the purpose such as the eye fundus image pickup in theophthalmic section, the eye fundus image pickup in the adult diseaseexamination, the eye fundus image pickup in the glaucomatousexamination, or the eye fundus image pickup in the macular degenerationexamination and the purpose-by-purpose fixation target setting storingunit for storing settings with respect to the movement operation of thefixation target and the presenting position thereof in accordance withthe purpose. Therefore, when the purpose is changed to perform the eyefundus image, settings with respect to the movement operation of thefixation target, the presenting position thereof, and the like can beconducted only by selecting the purpose. Thus, it is unnecessary tochange plural settings with respect to the movement operation of thefixation target and the presenting position thereof, so that thesettings can be easily changed in a short time.

1. An ophthalmic image pickup apparatus comprising: a fixation targetfor leading a line of sight of an eye to be examined; purpose settingmeans for setting an image pickup purpose of the ophthalmic image pickupapparatus; fixation target moving method storing means for storing amoving method of the fixation target corresponding to the image pickuppurpose set by the purpose setting means; and fixation target movementcontrol means for controlling a movement of the fixation target, whereinthe fixation target movement control means controls the movement of thefixation target in accordance with the moving method of the fixationtarget which corresponds to the set image pickup purpose and is storedin the fixation target moving method storing means.
 2. An ophthalmicimage pickup apparatus comprising: a fixation target for leading a lineof sight of an eye to be examined; purpose setting means for setting animage pickup purpose of the ophthalmic image pickup apparatus; fixationtarget setting position storing means for storing a setting position ofthe fixation target corresponding to the image pickup purpose set by thepurpose setting means; and fixation target movement control means forcontrolling a movement of the fixation target, wherein the fixationtarget movement control means controls the movement of the fixationtarget in accordance with the setting position of the fixation targetwhich corresponds to the set image pickup purpose and is stored in thefixation target setting position storing means.